One part that I found particularly odd: when they pulled him aside to question him, I tried to wait for him, but was told I needed to continue through a one-way, armored door with no window. I later found out that they asked him why his ticket said he was traveling with family when his family wasn’t with him. Fortunately, our mother was pretty far behind us in line, didn’t realize he had been pulled aside for questioning, and called for him to hurry up. I’m told that allayed their fears and he was released.
He came out of it pretty rattled. We had already been forced to stand in line for over an hour--which was taking a toll on our elderly grandparents, who weren't permitted to sit. He was visibly shaken and disoriented.
We eventually came to the conclusion that he looked a little too American. Cheap, university-student clothing (e.g., free sunglasses handed out by a university). They must’ve though he was trying too hard to fit in. He didn’t set off any alarms; he hadn't even made it to the security checkpoint yet. They pulled him out of the line.